The peri-arrest period is the time either before or immediately following a full cardiac arrest, when the patient’s condition is unstable.  Paramedics caring for a patient in the peri-arrest period (the so-called “crashing patient”) have an opportunity to significantly improve outcomes in comparison to patients in cardiac arrest, provided they are able to recognize and respond to signs of imminent deterioration.

A significant body of research demonstrates that many patients exhibit signs of clinical deterioration before experiencing cardiac arrest.  The following features indicate that a patient is at high risk of being peri-arrest:

• Shock/hypotension (systolic blood pressure<90 mm Hg), pallor, sweating, cold clammy extremities, confusion or impaired consciousness, poor oxygenation
• Syncope: transient loss of consciousness due to global reduction in blood flow to the brain
• Myocardial ischemia: typical ischemic chest pain and/or evidence of myocardial ischemia on 12-lead ECG.
• Heart failure: pulmonary edema and/or raised jugular venous pressure
• Cardiac arrhythmias (relatively common in the peri-arrest period)

The specific clinical findings will dictate the need for appropriate immediate treatment in the peri-arrest period.  Depending on the nature of any underlying arrhythmia and clinical status of the patient, in particular the presence or absence of adverse features, immediate treatment options for patients in the peri-arrest period can be divided into four categories:

1. No treatment needed
2. Simple clinical interventions (e.g., Vagal maneuvers)
3. Pharmacological therapies
4. Electrical therapies (e.g., cardioversion or pacing)

Most drugs act slowly, and less reliably, than electrical treatments, so defibrillation or cardioversion is generally preferred for unstable patients with adverse features.  Once treated, paramedics must continue to assess and monitor the patient to detect any additional abnormalities that may require treatment. 

ACPs and above may consider the use of prophylactic antiarrhythmics following the successful termination of ventricular fibrillation or ventricular tachycardia.  Although there are no studies that demonstrate improvement in long-term survival, the continued use of antiarrhythmic agents (particularly in cases where one was used to terminal a lethal arrhythmia) may be beneficial in maintaining a stable, perfusing rhythm and is supported by current American Heart Association Emergency Cardiovascular Care guidelines. 

Non-technical skills such as leadership, teamwork, communication and situational awareness enables a more effective response to the deteriorating patient and are critical to ensuring an appropriate response to patients in the peri-arrest period.

If the patient is palliative or otherwise at the end of their life, treat in accordance with relevant clinical practice guidelines.